Reposting from here, as scrolling down is different than scrolling up.
On my android phone (I don’t log into SDMB on my phone), and “Samsung Internet”, scrolling down towards the bottom of the thread, it sometimes get stuck at around 18 of whatever posts, and not go down any further. There’s an ad there and refuse to go any more. I can click on the 18/whatever box, use the scroll bar to jump around the blockage, but then that box disappears so I have to remember what the last post had written to get back up to it. The 18/whatever box shows up at the bottom at the “stuck” point, so I’m guessing Discourse thinks it’s at the bottom and doesn’t need to go any further downward.
Scrolling up (towards the top of the page), I sometimes get “jumps”, either down or up a couple of posts (not sure which), at the ads. This I understand to be a known issue because of reasons. (I don’t remember where I read this.)
A different Discourse website I go to doesn’t have these scrolling problems, but it doesn’t have the interwoven ads (if that’s the term?).